A variety of interlocking type masonry building blocks are available for the construction of load bearing and non-load bearing walls. Such blocks are laid in courses without the use of mortar as done in conventional masonry. As a general rule, conventional masonry wall blocks are heavy and relatively difficult to handle. Such blocks typically include projections that mate with corresponding indentations on adjacent blocks. However, many of these projections are relatively small and thus there is an inherent weakness in the block. Also the use of small projections and small indentations means that the blocks have to be built to close tolerances which make the blocks more expensive. The typical small projections may be easily broken or chipped off prior to or during construction which means that many blocks are discarded adding to the expense. Further, the available blocks do not have suitable provisions for the installation of embedded utilities. Thus there is a need for masonry wall blocks that are relatively light and easier to handle that are cost effective to manufacture and easily assembled into a more stable and dependable wall structure with provisions for embedding utilities.
A U.S. Pat. No. 8,640,407 of Saleh H. Alsayed, Mohammed S. Alhaddad and two inventors of the present invention disclose a rectangular shaped interlocking building block comprising a pair of exterior sides and an upper and a lower longitudinally extending horizontal faces and a pair of opposite vertical ends and wherein the building blocks include a pair of side members and wherein each of the side members includes a vertically extending exterior rib on an inner side thereof; a generally rectangular intermediate section is disposed between the side members in an abutting relationship and wherein the intermediate section defines a rectangular shaped vertical recess between the side members and a recess that extends between a bottom of one of the side members and the top of an adjacent block. The rectangular rib and vertical recesses are constructed and dimensioned so that one rib fits loosely but closely within the recess and the intermediate section includes a pair of elliptical shaped vertical passageways.
Notwithstanding the above, it is presently believed that there is a need and a potential commercial market for the improved building blocks and wall structure according to the present invention. There should be a need and a potential market for such masonry building blocks because they are strong, will support heavy vertical loads and at the same time are relatively lightweight. In addition, the masonry building blocks in accordance with the present invention have a high resistance to wind and other lateral forces and can be manufactured and sold at a competitive price. Still further the weight and costs of such blocks are further reduced by the rectangular vertical passageways that extend through the blocks.